If there is one characteristic that marks out books for older children, it is not always the advent of hormones or divorce proceedings. It's gore.

At the younger end of the older spectrum, we have a gentle book such as A Cat Called Penguin (Scholastic £4.99), in which a fat agreeable feline unites two former enemies – Alfie (owner) and Grace (arriviste) – in their quest to find him. Author Holly Webb delicately threads in a minor dementia subplot. But more pertinently, Penguin gets to disembowel a pigeon in the bathroom, albeit off-screen – something that never happened with Mog.

Francesca Simon has written scads of books since the Horrid Henry series. It's just as well, because Henry is perhaps the most overrated franchise in kid-fic. Pre-teen Simon, though, is so much better than simple Simon. The Sleeping Army (Profile £9.99) finds a bewildered 21st-century everygirl, Freya, forced into an impossible quest. But this is a present in which the old pagan gods were never superseded by Christianity. There are shades of Philip Pullman as Freya finds Odin, Thor et al moribund and senile. She sulkily sets off on a quest to restore their power in the company of warring siblings Alfi and Roskva, and a foul-smelling berserker named Snot. As they journey – literally to Hel and back – the yuck goes exponential. If there is a vat of fermented fish-guts, rest assured it will be upturned. Parents will smirk at the parody of modern society, in which fanes (churches) are half-full of hypocrites trying to get their kids into good fane schools. Their progeny will like the backchat from this believable anti-heroine. Oh, and the terrible incident involving giant's wee.

Anyone who enjoyed the works of Joan Aiken and Jan Pienkowski at an impressionable age will coo fondly over the reissue of 1971's The Kingdom Under the Sea (Jonathan Cape £12.99), Aiken's retelling of a series of eastern European folk tales. It too, is chock-full of ghastliness, as vintage children's tales used to be. Pienkowski's illustrations are whimsically macabre, and yet, there is something a little close to homework about these weird old tales with their spurious Russian plot-twists and incomprehensible Balkan motivations. Simon, by contrast, brings Norse mythology to vibrant life for tweens with mobile phones.

There's a temptation to set the bar low when reading a debut children's book from an actor. But Mackenzie ("Pirates of the Office") Crook's Windvale Sprites (Faber £9.99) is just fantastic. Ostensibly, it's a book about fairies. But these aren't girly sprites, these are diffident, humanoid dragonflies that protagonist Asa sets out to capture, before slowly realising the full horror of that Victorian urge to pin and mount. Yuck factor? Asa realises too late that leaving a dead sprite in a shoebox next to a hot water pipe for a few days isn't a good idea. The book gets blown off course slightly four-fifths of the way in, when Crook's sense of verisimilitude wobbles. But this is still a gripping moral thriller that outclasses the work of many professionals.

Farm Boy (HarperCollins £5.99), Michael Morpurgo's slim sequel to War Horse, riskily abandons the horse's eye view. What happened next to the half-thoroughbred war veteran Joey and his master Albert is told as a story within a story, two generations on. If you are fond of Morpurgo, the loss of Joey's stoical musings won't matter. The warm horsey glow as steadfastness triumphs over adversity is enough. But for those coming to it from the stage play or forthcoming film, it's hardly an electrifying read – no suppurating wounds, no stench of trench.

While not as gallivantingly icky as Simon's Sleeping Army, Sapphire Battersea (Doubleday £12.99), Jacqueline Wilson's 654th novel (or thereabouts) packs in plenty of bloody tubercular coughs and end-of-the-pier freaks (kindly drawn). This is the next book along in the Hetty Feather series, in which Wilson's care home heroine Tracy Beaker is basically reincarnated as a foundling hospital girl 135 years previously. Plucky Sapphire (formerly Hetty) goes out to earn her keep, fuelled by Wilson's class rage and carnivorous sense of yearning.

Even better, though, is Lauren Child's Look into My Eyes (HarperCollins £12.99) which features Ruby Redfort, a Clarice Bean bit-parter now enjoying her own spin-off series. Mathematician Marcus du Sautoy lends a hand with the puzzles thrown in the path of this rich, pampered but razor-sharp American teen sleuth. The villains are cartoonishly bad, in the most enjoyable way. And if it lacks any actual ooze, Ruby makes up for it in being witty and stylish. Having pretty much abandoned the little ones for the tween market, the writer really ought to change her name to Lauren Older Child by deed poll.